This invention is directed to twin wire web forming machines and in particular to a sinuous path web former suitable for use with grades of stock possessing slow to average draining rates.
There is in the paper making industry an extensively developed history of web formation using converging twin wire machines, commencing chronologically with cardboard manufacture, and leading up to present day high speed machines for manufacturing newsprint.
One such machine, known commercially as the "Papriformer" (Trademark) provides a substantially continuously curving sinuous or `S` shaped path which is traversed by both of the wires in web sandwiching relation, as shown in Canadian Pat. No. 731,383 issued Apr. 5, 1966, de Montigny et al.
This continuously sinuous arrangement of the web forming wire path appears superficially like the arrangement shown in U.S. Pat. No. 3,565,757, Jordansson, Feb. 23, 1971 wherein FIG. 2 shows an intermediate extended straight path having a series of suction boxes underlying one of the wires; being located between oppositely-directed curved portions of the travel path of the two wires, where the web is trained around forming rolls. However, the dynamics of dewatering utilizing suction boxes and the extent and arrangement of the respective wire runs differ markedly between the two referenced arrangements, leading to significant differences in operational characteristics as well as first costs.